Electroluminescent element

ABSTRACT

The main object of the present invention is to provide a method for producing an EL element for realizing the high luminous efficiency, the high light takeout efficiency, the simplicity of the production process, and the formation of highly fine patterns. In order to achieve the above-mentioned object, the present invention provides a method for producing an EL element wherein at least one organic EL layer constituting the EL element is patterned by the use of a photolithography method.

This application is a division of U.S. Ser. No. 10/389,112 filed Mar.14, 2003, which is a division of U.S. Ser. No. 09/960,088 filed Sep. 21,2001, which U.S. applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a method for producing anelectroluminescent element (may be referred to as an abbreviation of EL)in which a pattern is formed.

EL elements attract attention as spontaneously emitting flat paneldisplay elements in which positive holes and electrons, which have beenpoured into from opposed electrodes, are combined in a luminous layer togenerate energy, and the energy excites fluorescent material in luminouslayer to emit light of a color corresponding to the fluorescentmaterial. Among them, an organic thin film EL display using an organicmaterial as a luminescent material has such a high luminous efficiencythat high intensity luminescence can be realized even if applied voltageis a little less than 10 V, is possible to emit light with a simpleelement structure, and is expected to be applied to low-cost simpleexpression displays such as advertisements and the like in whichspecific patterns are emitted and displayed.

In the production of a display using such an EL element, patterning onan electrode layer and an organic EL layer is usually put into practice.Methods of EL element patterning include a vapor deposition method of aluminescent material via a shadow mask, a method of separately paintingthrough inkjet, a method of destroying specific luminescent pigmentthrough ultraviolet irradiation, a screen printing method, and others.However, these methods could not provide an EL element being possible torealize all of the high luminous efficiency, the high light takeoutefficiency, the simplicity of the production process, and the formationof highly fine patterns.

The present invention has been achieved in order to solve theabove-mentioned problems. It is a main object of this invention toprovide a method for producing an EL element for realizing the highluminous efficiency, the high light takeout efficiency, the simplicityof the production process, and the formation of highly fine patterns.

SUMMARY OF THE INVENTION

In order to achieve the object mentioned above, the present inventionprovides a method for producing an EL element, wherein at least oneorganic EL layer constituting the EL element is patterned by the use ofa photolithography method.

According to a method for producing an EL element in the presentinvention, because the EL element is obtained by patterning at least oneorganic EL layer within the EL element by the use of a photolithographymethod, when compared to the conventional vapor deposition patterningmethod, the EL element can be produced relatively easily and in low costbecause no vacuum equipment with high precision alignment mechanism andothers are needed. On the other hand, when compared to the patterningmethod by the use of an inkjet system, the production method of thepresent invention is preferable in the point of no need of carrying outpreprocessing to constructions and substrates aiding patterning, andfurther the production method can be considered to be preferable tohigher precision pattern forming because of the relationship to thedischarge accuracy of an inkjet head. Thus, according to the EL elementproduction method of the present invention, a highly fine EL element canbe obtained relatively easily and in low cost.

In the above-mentioned invention, it is preferable that an organic ELlayer made by patterning with the use of the above-mentionedphotolithography method is a luminous layer. Because in an EL element, aluminous layer is an indispensable layer and can obtain a highly finepattern that is needed in case of light emission.

Further, in the above-mentioned invention, it is preferable that theabove-mentioned luminous layer is insoluble in a photoresist solvent, aphotoresist developing solution, and a photoresist peeling liquid, and aphotoresist is insoluble in a solvent that is used in forming theabove-mentioned luminous layer. Although depending on the kinds ofphotolithography methods such as, for example, a method of using dryetching, a method of using a dry film and the like, in case where thegeneral wet photolithography method is used, it is preferable to use aluminous layer and a photoresist that satisfy such requirements.

In addition, in the above-mentioned invention, it is preferable that theabove-mentioned luminous layer is a luminous layer in which differenttypes of luminous layers are formed by the use of the photolithographymethod in plural times. Because when the luminous layer is formed indifferent types of plural luminous layers, full coloring is possible,for example, by selecting red, green, blue and the like.

In this case, it is preferable that a solvent used for forming aluminous layer in the above-mentioned luminous layers, which are formedin two times and after, is a poor solvent to the previously formedluminous layer. Because a solvent for forming a luminous layer that isused in a luminous layer to be newly formed is a poor solvent to thepreviously formed luminous layer, so no mixed color will be caused whena luminous layer is further formed on the previously formed luminouslayer.

In this case, it is preferable that the solubility of the previouslyformed luminous layer to the solvent used for forming luminous layersformed in two times and after is 0.1 g or less/g of solvent at 25° C.under 1 atmospheric pressure. This is the reason that, if the solubilityis in this degree, even when a new luminous layer is formed on thepreviously formed luminous layer, the previously formed layer will notbe dissolved in a solvent to cause mixed color.

Furthermore, it is also preferable that the above-mentioned luminouslayers to be formed in plural times are formed in the order of the shortwavelength of light obtained from them.

Generally, when two kinds of a luminescent material emitting light ofhigh energy short wavelength and a luminescent material emitting lightof low energy long wavelength are mixed, the light emission from theluminescent material emitting light of long wavelength becomes to bemain. In the present invention, since luminous layers are planed to beformed in the order of the short wavelength of light emitted from them,a luminescent material for a luminous layer to be formed later becomesto be a luminescent material emitting light of a long wavelength, andeven if the luminescent material used for forming the previously formedluminous layer is mixed in a luminous layer to be formed later, theshort wavelength luminescent material in the previously formed luminouslayer that mixed in will hardly emit light, resulting in extremelylowering the possibility of causing problems like mixed color andothers.

Like this, in case where luminous layers are formed in plural times, itis preferable that the above-mentioned luminous layers are three typesof luminous layers emitting red, green and blue light. Because in orderto make light emit in full color, it is generally preferable to makelight emit in the three primary colors of red, green and blue.

Moreover, in the present invention, the above-mentioned organic EL layerthat is made by patterning with the use of a photolithography method maybe a buffer layer. In the present invention, it is preferable to use aphotolithography method as mentioned above when a luminous layer ispatterned, however the use of a photolithography method is not limitedto this, the buffer layer may be patterned with the use of aphotolithography. In particular, in an EL element in which a luminouslayer is comprised of an organic polymer, it is preferable to combine abuffer layer and a luminous layer from the aspect of luminousefficiency, and on this occasion, through both layers are patterned withthe use of a photolithography method, a cheap and high quality ELelement can be produced.

In this case, it is preferable that the above-mentioed buffer layer isinsoluble in a photoresist solvent and a photoresist peeling liquid, anda photoresist is insoluble in a solvent used for forming theabove-mentioned buffer layer. This is the reason that, similarly to thecase of a luminous layer as mentioned above, though depending upon thekinds of photolithography methods, it is necessary to satisfy theabove-mentioned requirements in a photolithography method in which allprocedures are carried out in wet conditions.

And, further, it is preferable that after a buffer layer that isinsoluble in a photoresist solvent, a photoresist peeling liquid and asolvent to be used for forming a luminous layer is patterned and formedwith the use of a photoresist that is insoluble in a solvent used informing the buffer layer, a luminous layer that is insoluble in aphotoresist solvent, a photoresist developing solution, and aphotoresist peeling liquid is patterned and formed with the use of aphotoresist that is insoluble in a solvent to be used in forming theluminous layer. As mentioned above, in an EL element in which a luminouslayer is comprised of an organic polymer, it is preferable to combine abuffer layer with a luminous layer. Because it is preferable that inthis case, a buffer layer that satisfies the above-mentionedrequirements is first formed by a photolithography method, then aluminous layer that satisfies the above-mentioned requirements, isformed.

In the present invention, the above-mentioned patterning by the use of aphotolithography method may be a patterning that after a photoresist ispatterned in such a way that the photoresist is applied on an organic ELlayer to be patterned, exposed and developed, the organic EL layer inthe part where the photoresist has been removed is removed with dryetching.

Because it becomes possible to form highly finer pattern by the use of amethod with which an organic EL layer can be dry etched like this.

In this case, the above-mentioned dry etching is preferable to bereactive ion etching. It is because the organic EL layer can beeffectively removed by the use of reactive ion etching.

Furthermore, it is preferable to use a simple substance of oxygen or agas containing oxygen in the above-mentioned dry etching. Because theuse of a simple substance of oxygen or a gas containing oxygen caneffectively remove the organic EL layer without affecting on glass andITO with oxidation reaction.

In addition, it is preferable to use atmospheric-pressure plasma in theabove-mentioned dry etching. It is because the use ofatmospheric-pressure plasma makes it possible to delete the vacuumprocess and to carry out patterning with high productivity.

Further, in the present invention, the above-mentioned patterning by theuse of a photolithography method is preferable to be a patterning thatafter a photoresist is patterned in such a way that the photoresist isapplied on an organic EL layer to be patterned, exposed and developed,the organic EL layer in the part where the photoresist has been removedis removed in an ultrasonic bath.

It is because the use of such a method makes it possible to carry outhigh precise patterning without problems including the narrowing of eachpattern and the outflow of materials for the organic EL layer, in thepatterning of the organic EL layer with the use of a photoresist.

The present invention provides an EL element having at least onepatterned organic EL layer, and the EL element wherein that it does nothave any of partition, a structure aiding patterning, and surfacetreatment aiding patterning.

The EL element of the present invention has an advantage of low costbecause it does not have a partition and others like this.

Further, the present invention provides an EL element having at leastone organic EL layer, and the above-mentioned EL element layer whereinit is a patterned luminous layer and the width of an area with unevenfilm thickness that is formed at the edge of the above-mentionedpatterned luminous layer is 15 μm or less.

In the EL element of the present invention, because the width of an areawith uneven film thickness is 15 μm or less, it is possible to make thedistance between patterns to be small and to make a highly fine pattern.Here, “an area with uneven film thickness” indicates an area where thefilm thickness is decreased from that of a flat part, that is, an areawhere the film thickness is equal to or less than 90% of the averagefilm thickness of the flat part.

Furthermore, the present invention provides an EL element having atleast one organic EL layer, and the above-mentioned EL layer wherein itis plural luminous layers that can emit light with plural colors and thedistance between adjacent luminous layers emitting different colors is30 μm or less. Since the distance between pixels can be made small likethis, a higher quality image can be displayed.

In these, it is preferable to have at least a substrate, an electrodelayer formed on the above-mentioned substrate in the form of a pattern,and an insulating layer that is formed so as to cover the edge part ofthe above-mentioned electrode layer and the non-luminous layer of theelement. Because it is possible to prevent shorts in parts unnecessaryfor luminescence and to decrease defects due to short of elements andthe like to make an element that has a long life and can obtain stableluminescence.

According to the present invention, since the EL element is obtained bypatterning at least one organic EL layer within the EL element by theuse of a photolithography method, when compared to the conventionalvapor deposition patterning method, the EL element can be producedrelatively easily and in low cost because no vacuum equipment withalignment mechanism and others are needed. On the other hand, whencompared to the patterning method by the use of an inkjet system, theproduction method of the present invention is preferable in the point ofno need of carrying out preprocessing and others to constructions andsubstrates aiding patterning, and further the method can be consideredto be preferable in the formation of higher precision patterns becauseof the relationship to the discharge accuracy of an inkjet head. Thus,according to the EL element production method of the present invention,a highly fine EL element can be obtained relatively easily and in lowcost.

Further, according to the present invention, an EL element and theproduction method thereof will be provided for realizing all of thefollowing subjects; no mixing of impurities in the luminous layer, thehigh luminous efficiency and the high light takeout efficiency, thesimplification of production processes, the mass production system, thepattern formation being possible to emit highly fine and uniform light,and decreasing in crosstalk.

To be more concrete, for example, it is possible to decrease crosstalkin the drive of a simple matrix element by patterning a buffer layer.And, through patterning a buffer and luminous layers that are made byapplication, it is possible to carry out laser removal and insolublepart removal usually carried out by pulling out at the same time, andthus it is possible to simplify the processes. Further, it is alsopossible to simplify the processes from the view point of the followingfact; there is no need to use any of a partition, a structure havingink-repellent property to aid patterning and surface treatment havingink-repellent property to aid patterning. Moreover, the presentinvention is excellent in the points of being able to control andpattern the color of emitted light in any of an EL element emittinglight in an optional pattern and an EL element emitting full colorlight, and further in an EL element using a flexible substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) through FIG. 1(l) shows one example of the production methodof an EL element in the present invention, illustrating a flow diagramindicating the procedures of producing an EL element with single colorby carrying out the patterning of a buffer layer.

FIG. 2(a) through FIG. 2(n) shows another example of the productionmethod of an EL element in the present invention, illustrating a flowdiagram indicating the procedures of producing an EL element with fullcolor display by carrying out the patterning of a luminous layer withthree colors.

FIG. 3 is an expanded sectional view showing the expanded section of theedge part of a luminous layer in an EL element of the present invention.

FIG. 4 is an expanded sectional view showing the expanded section of theedge part of a luminous layer formed by the conventional inkjet method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, first the production method of an EL element in thepresent invention will be described, and then the EL element of thepresent invention that can be produced by the EL element productionmethod and has such a new characteristics that cannot be found in usualelements will be described.

A. The Production Method of an EL Element.

The production method of an EL element in the present invention whereinat least one organic EL layer constituting an EL element is patterned bythe use of a photolithography method.

In the production method of an EL element in the present invention,because at least one organic EL layer constituting an EL element isformed by a photolithography method, no vacuum device and the like areneeded, and the patterning of the organic EL element can be carried outeasily and at low cost when compared to the conventional vapordeposition method that is carried out through a shadow mask. On theother hand, when compared to the patterning by an inkjet method, highlyfine patterning can be carried out without the pretreatment of asubstrate and the necessity of setting liquid-repellent heights betweenpatterns and others. That is, according to the production method of anEL element in the present invention, a high quality EL element havinghighly fine pattern can be obtained at low cost.

In the following, each composition in the production method of an ELelement in the present invention will be described concretely.

(Organic EL Layer)

An EL element in the present invention has at least one patternedorganic EL layer, and to be concrete, the EL element is comprised of atleast the first electrode layer, an EL layer formed on theabove-mentioned first electrode layer, and the second electrode layerformed on the above-mentioned EL layer, and at least one organic ELlayer to be patterned is contained in the above-mentioned EL layer.

Here, at least a luminous layer is necessary to be included in the ELlayer. In addition, a buffer layer, a positive hole transporting layer,a positive hole injection layer, an electron transporting layer, anelectron injection layer and others may be combined.

Furthermore, the above-mentioned organic EL layer to be patterned may beany layer constituting the above-mentioned EL layer, however in thepresent invention, a luminous layer or a buffer layer is preferable.Among them, a layer that a luminous layer is patterned as an organic ELlayer is preferable from the viewpoint of exhibiting the effect of thepresent invention to the fullest. In addition, from the aspect ofluminescence properties, this layer in which a luminous layer and abuffer layer are patterned as an organic EL element is considered to bethe most preferable example.

To be concrete, a preferable example is such an EL layer that a bufferlayer is patterned and formed on the first electrode layer as an organicEL layer by a photolithography method, further on the organic EL layer,a luminous layer is patterned and formed as an organic EL layer by aphotolithography method, and further on the second organic EL layer, thesecond electrode layer is formed. In particular, the most preferableexample is a full colored EL element in which the above-mentionedluminous layer is three kinds of luminous layers and is patterned andformed three times by a photolithography method.

In the present invention, the production method is characterized in thatin case where such an organic EL layer is patterned, the patterning iscarried out by the use of a photolithography method. And other layerscan be produced by the method conventionally used.

(Photolithography Method)

The production method of the EL element of the present invention whereinthe patterning of the above-mentioned organic EL layer is carried out bya photolithography method. The photolithography method is a method toform an optional pattern corresponding to an exposure pattern by the useof a property that the solubility of exposure part in a film is changedby exposure. In the following, the photolithography method will bedescribed.

(Photoresists)

A photoresist that can be used in the present invention is not limitedto a positive photo resist or a negative photoresist, but is preferableto be insoluble in a solvent to be used for forming an organic EL layer,including a luminous layer.

As photoresists that can be used concretely, photoresists of novolacresin series and rubber plus bisazide series can be listed.

(Photoresist Solvents)

In the present invention, as photoresist solvents to be used when theabove-mentioned photoresist is coated, it is desirable to use such asolvent that does not dissolve organic EL materials, including luminouslayer materials, in order to prevent the mixing and dissolving of theabove-mentioned organic EL layer, including a luminous layer, andphotoresist materials in case of the film formation of a photoresist andto keep original luminous properties. Considering this point, asphotoresist solvents that can be used in the present invention, it ispreferable to select a solvent that the solubility of materials forforming organic EL layer, including materials for forming luminouslayers, is 0.001 or less (g/g solvent) at 25° C. under 1 atmosphericpressure, and more preferable to select a solvent that theabove-mentioned solubility is 0.0001 or less (g/g solvent).

For example, as solvents that can be used when a material for forming abuffer layer dissolves in a solvent of water series and a luminous layerdissolves in a nonpolar organic solvent, including aromatic series, thefollowing solvents can be listed: ketones, including acetone and methylethyl ketone; cellosolve acetates, including propylene glycolmonoethylether acetate, propylene glycol monomethylether acetate,ethylene glycol monomethylether acetate, ethylene glycol monoethyletheracetate; cellosolves, including propylene glycol monoethyl ether,propylene glycol monomethyl ether, ethylene glycol monomethyl ether,ethylene glycol monoethyl ether; alcohols, including methanol, ethanol,1-butanol, 2-butanol, cyclohexanol; ester solvents, including ethylacetate, butyl acetate; cyclohexane, decalin, and others. However,solvents other than the listed solvents are also usable if they satisfythe requirements, and mixed solvents of two or more solvents may beused.

(Photoresist Developing Solutions)

Further, photoresist developing solutions that can be used in thepresent invention are not especially limited unless they do not dissolvematerials forming the above-mentioned organic EL layers. To be concrete,organic alkaline developing solutions, which have been generally used,can be used, however in addition, inorganic alkali developing solutionor aqueous solutions that can develop resists can be also used. After aresist is developed, it is preferable to wash the resist with water.

As a developing solution to be used in the present invention, it ispreferable to use a developing solution that the solubility of materialsfor forming organic EL layer, including materials for forming luminouslayers, is 0.001 or less (g/g developing solution) at 25° C. under 1atmospheric pressure, and more preferable to select a developingsolution that the above-mentioned solubility is 0.0001 or less (g/gdeveloping solution)

(Photoresist Peeling Liquids)

Furthermore, as photoresist peeling liquids that can be used in thepresent invention, it is necessary to dissolve a photoresist layerwithout dissolving the above-mentioned organic EL layer, and photoresistsolvents as mentioned above can be used as they are. And when a positiveresist is used, it is also possible to peel off the resist by the use ofa liquid listed as a resist developing solution after being subjected toUV exposure.

Moreover, it is also possible to use solvents, including strong alkaliaqueous solution, dimethylformamide, dimethylacetamide,dimethylsulfoxide, and N-methyl-2-pyrrolidone, and their mixture,commercially available resist peeling liquid. After the resist is peeledoff, it is rinsed with 2-propanol and the like, and further may berinsed with water.

(Patterning Methods)

Patterning by a photolithography method used in the present invention isa method to pattern an organic EL layer and is concretely carried out asfollows:

When a positive photoresist is used, after an organic EL layer is formedon the whole surface, a photoresist solution in which theabove-mentioned photoresist material is dissolved in the above-mentionedphotoresist solvent is coated whole on the surface and dried to form aphotoresist layer in the first place. Then, this photoresist layer issubjected to pattern exposure and the photoresist on the exposed part isdeveloped using a developing solution as mentioned above. By thisdeveloping, only the photoresist on the unexposed part is remained. Andremoving the organic EL layer on the part not covered with thephotoresist patterns an organic EL layer.

Furthermore, a method to form the whole surface of an organic EL layeras mentioned above is similar to the method of forming a usual organicEL layer and is not especially limited. However, other than the vapordeposition method, many coating methods can be listed, that is, theelectrodeposition method, the spin coating method in which a meltingliquid, solution or mixed solution of material is used, the castingmethod, the dipping method, the bar coating method, the blade coatingmethod, the roll coating method, the gravure coating method, theflexographic printing method, the spray coating method and the like.

In the photolithography method used in the present invention, asmentioned above, after a photoresist is coated on an organic EL layer tobe patterned, exposed and developed, the organic EL layer on the partwhere the photoresist is removed may be removed by the use of dryetching.

Since a photoresist layer is usually formed in considerably thicker filmthan that in an organic EL layer, the organic EL layer can be removed bywholly carrying out dry etching.

In this case, the film thickness of the photoresist layer is preferableto be within the range of 0.1 to 10 μm, and more preferable to be withinthe range of 0.5 to 5 μm. When the film thickness is kept in such arange, dry etching with high processing accuracy can be achieved withholding the resist function of the photoresist.

Combining the dry etching method with a part of the photolithographymethod make it possible to make the edge part of etching more sharp.Consequently the width of uneven film thickness area existing at theedge part of the pattern can be made narrower. As a result, it will beconfirmed that highly finer patterning is possible.

As a dry etching method used in the present invention, the dry etchingis preferable to be a reactive ion etching. It is because that by theuse of a reactive ion etching, an organic film is chemically reacted anddecomposed to chemical compounds in small molecular weights, and thatsince these chemical compounds can be removed from the substrate bybeing evaporated and vaporized, it becomes possible to performprocessing with high precision etching in short time.

Further, in the present invention, it is preferable to use a simplesubstance of oxygen or a gas containing oxygen in case of theabove-mentioned dry etching. By the use of a simple substance of oxygenor a gas containing oxygen, it is possible to decompose and remove anorganic film through the oxidation reaction, unnecessary organic mattercan be removed from the substrate, and it is possible to performprocessing with high precision etching in short time. Further, in thiscondition, because transparent oxide conductive films like usually usedITO and others are not etched, the dry etching is effective from theview point of purifying the surface of the electrode without injuringthe electrode properties.

Moreover, in the present invention, it is preferable to useatmospheric-pressure plasma in the above-mentioned dry etching. By theuse of atmospheric-pressure plasma, dry etching in which a vacuum deviceis usually necessary can be carried out under atmospheric pressure. As aresult, it is possible to shorten the processing time and decrease thecost. In this case, although the etching can utilize the phenomenon thatorganic matter is oxidized and decomposed by plasma oxygen in the air,it is also possible to control the gas composition in the reactionatmosphere by the substitution and circulation of the gas.

In the photolithography method used in the present invention, there maybe such a patterning that after a photoresist is applied on an organicEL layer to be patterned, exposed and developed, the organic EL layer inthe part where the photoresist has been removed is removed with the useof a solvent. The solvent to be used in this time is needed to dissolveor peel off the luminous layer without peeling off the photoresist, andany solvent satisfying the requirements can be selected other than thesolvent to be applied on the luminous layer.

In the photolithography method used in the present invention, there maybe such a patterning that after a photoresist is applied on an organicEL layer to be patterned, exposed and developed, the organic EL layer inthe part where the photoresist has been removed is removed in anultrasonic bath. The solvent to be used is needed to dissolve or peeloff the luminous layer without peeling off the photoresist, and anysolvent satisfying the requirements can be selected other than thesolvent to be applied on the luminous layer.

It is because the use of such an ultrasonic bath makes it possible tocarry out high accuracy patterning without problems, including thenarrowing of each pattern and the outflow of materials for the organicEL layer, in the patterning of the organic EL layer with the use of aphotoresist. Such a patterning is preferable from the viewpoint of beingpossible to perform a short-time patterning with high precision.Further, also in case where the above-mentioned photoresist isdeveloped, this ultrasonic bath may be used.

In the present invention, as the ultrasonic conditions used in theultrasonic bath, the bath is preferable to be used for 0.1 to 60 secondsat the frequency of oscillation of 20 to 100 kHz at 25° C. In such aconditions, a short-time patterning with high precision can be realized.

(Buffer Layer)

In the present invention, on an EL layer that is sandwiched between twoelectrode layers as mentioned above, at least one layer is needed to bean organic EL layer to be patterned and it is preferable to be formed bypatterning a buffer layer or a luminous layer as an organic EL layer asmentioned above. In the following, first this buffer layer will bedescribed.

A buffer layer in the present invention is a layer containing organicmatter, especially an organic conductive material and the like, whichlayer is provided between the anode and a luminous layer or between thecathode and a luminous layer so that electric charges may be easilyinjected into the luminous layer. For example, a buffer may be aconductive polymer having a function of raising the injection efficiencyof positive holes into the luminous layer and making the unevenness ofelectrodes and the like flat.

For a buffer layer to be used in the present invention, when itselectric conductivity is high, the buffer layer is desirable to havebeen patterned so as to keep the diode properties of an element and toprevent crosstalk. Consequently, the buffer layer is desirable to bepatterned and formed by the present invention. Moreover, when theresistance of the buffer layer is high and others, a buffer layer thathas not been patterned may be accepted. And in case of an element wherea buffer layer can be eliminated, no buffer layer may be provided.

In the present invention, when both buffer layer and luminous layer arepatterned and formed as the above-mentioned organic EL layer by aphotolithography method, it is preferable to select a material forforming a buffer layer that is insoluble in a photoresist solvent and asolvent to be used for forming a luminous layer, more preferable toselect a material for forming a buffer layer that is insoluble in aphotoresist peeling liquid.

On the other hand, in case where a luminous layer is formed by vacuumfilm forming and the like and only a buffer layer is patterned as anorganic EL layer by a photolithography method, it is preferable toselect a material for forming a buffer layer that is insoluble in aphotoresist solvent and a photoresist peeling liquid.

As materials for forming a buffer layer to be used in the presentinvention, to be concretely, polyalkyl thiophene derivatives,polyaniline derivatives, polymers of positive hole transport materialsof triphenylamine and the like, sol-gel films of inorganic oxides,organic polymer films of trifluoromethane and the like, organic compoundfilms containing Lewis acid, and others can be listed. However thematerials are not especially limited if they satisfy the requirements onsolubility as mentioned above, it is also acceptable to satisfy theabove-mentioned requirements by reaction, polymerization or baking orthe like after film formation. Further, when the film of a luminouslayer is formed by the vacuum film formation and others, buffermaterials, positive hole injection materials and positive hole transportmaterials, which are generally used, can be used.

Moreover, as solvents to be used for forming a buffer layer in thepresent invention, it is sufficient that the solvent can be disperse ordissolve the materials for forming a buffer layer and are not especiallylimited, however when plural times of film formation for buffer layersare needed in patterning and the like with full colors, it is necessaryto use a solvent for a buffer layer that does not dissolve photoresistmaterials, and more preferable to use a solvent for a buffer layer thatdoes not dissolve a luminous layer. As a solvent for a buffer layer thatcan be used in the present invention, it is preferable to select asolvent that the solubility of resist materials is 0.001 or less (g/gsolvent) at 25° C. under 1 atmospheric pressure, and more preferable toselect a solvent that the above-mentioned solubility is 0.0001 or less(g/g solvent). And it is more preferable for a solvent for a bufferlayer to select a solvent that the solubility of luminous materials is0.001 or less (g/g solvent) at 25° C. under 1 atmospheric pressure, andespecially preferable to select a solvent that the above-mentionedsolubility is 0.0001 or less (g/g solvent) For example, water, alcohols,including methanol and ethanol, dimethylformamide, dimethylacetamide,dimethylsulfoxide, N-methyl-2-pyrrolidone and others can be listed.However, solvents other than the listed solvents are also usable if theysatisfy the requirements, and mixed solvents of two or more solvents maybe used.

An example of patterning of a buffer layer with the use of aphotolithography method like this will be described concretely withreference to FIG. 1.

FIG. 1 shows the procedure that a buffer layer and a luminous layer arepatterned to produce an EL element with a single color by the method ofthe present invention. First, as shown in FIG. 1 (a), buffer layer 3 isformed wholly on the first electrode layer 2 patterned on substrate 1.Next, as shown in FIG. 1 (b), positive resist layer 4 is formed onbuffer layer 3 and is prebaked. Next, as shown in FIG. 1 (c), thesurface is partly shielded the light with mask 5 and is subjected toultraviolet pattern exposure 6. Next, as shown in FIG. 1 (d), thesurface is developed with a resist developing solution and then washedwith water to remove the photoresist layer and the buffer layer of theexposed part. Next, as shown in FIG. 1 (e), the pattern of buffer layer3 covering the first electrode layer 2 can be formed by peeling off theresist with the use of the resist peeling liquid. Next, as shown in FIG.1 (f), luminous layer 7 is formed wholly on the first electrode layer 2patterned on substrate 1 and on buffer layer 3 prepared on the firstelectrode layer 2. Next, as shown in FIG. 1 (g), positive photoresistlayer 4 is formed on luminous layer 7 and is prebaked. Next, as shown inFIG. 1 (h), the surface is partly shielded the light with mask 5 and issubjected to ultraviolet pattern exposure 6. Next, as shown in FIG. 1(i), the surface is developed with a resist developing solution and thenwashed with water to remove the photoresist layer of the exposed part.Next, as shown in FIG. 1 (j), uncovered patterned luminous layer 7 isremoved by washing with a solvent for a luminous layer. Next, as shownin FIG. 1 (k), the resist is peeled off with a resist peeling liquid.Lastly, as shown in FIG. 1 (l), the second electrode layer 8 is formedto produce an EL element that emits EL luminescence 9 downward in thefigure.

(Luminous Layer)

In the next place, a luminous layer as an organic EL layer that ispatterned and formed by the present invention will be described.

As materials to form a luminous layer like this, any material, as longas it contains a material emitting fluorescence and emits lightemission, can be used and especially not limited. Although materials toform a luminous layer can possess both a light emission function and apositive hole transport function or an electron transport function, itis preferable that materials to form a luminous layer are insoluble inthe above-mentioned photoresist solvent, the above-mentioned photoresistdeveloping solution, and the above-mentioned photoresist peeling liquid.Further, in this case, as a material for a photoresist to be used when aluminous layer is patterned by a photolithography method, it ispreferable to use a material that is insoluble in a solvent to be usedfor forming the luminous layer.

As materials to form a luminous layer that can be used in the presentinvention, for example, the following materials can be listed.

1. Materials of Coloring Matter Series.

As materials of coloring matter series, cyclopendamine derivatives,tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazolederivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives,distyrylarylene derivatives, cyrol derivatives, thiophene cycliccompounds, pyridine cyclic compounds, perynone derivatives, perylenederivatives, oligothiophene derivatives, trifumanylamine derivatives,oxadiazole dimer, pyrazoline dimer, and others can be listed.

2. Materials of Metal Complex Series.

As materials of metal complex series, the following metal complexes andthe like can be listed; aluminum quinolinol complex, benzoquinolinolberyllium complex, benzoxazol zinc complex, benzothiazole zinc complex,azomethyl zinc complex, porphyrin zinc complex, europium complex, andothers, which complexes have Al, Zn, Be and others, or rare-earthmetals, including Tb, Eu, and Dy, as keymetals, and have oxadiazol,thiadiazol, phenylpyridine, phenylbenzoimidazole, quinoline structuresand others as ligands.

3. Materials of Polymer Series.

As materials of polymer series, polyparaphenylene vinylene derivatives,polythiophene derivatives, polyparaphenylene derivatives, polysilanederivatives, polyacethylene derivatives, polyfluorene derivatives,polyvinylcarbazole derivatives, the above-mentioned coloring matterseries materials, polymerized materials of metal complex seriesluminescent materials, and others can be listed.

In the present invention, it is more preferable to use theabove-mentioned polymer series materials as luminescent materials fromthe viewpoint of making the best use of the advantage that a luminouslayer can be formed with high precision by a photolithography methodwith the use of a coating liquid for a luminous layer.

4. Doping Materials.

Doping can be carried out for the purpose of improving the luminousefficiency in a luminous layer and of changing the wavelength of emittedlight. As this doping materials, for example, perylene derivatives,coumarin derivatives, rubrene derivatives, quinacridon derivatives,squalium derivatives, porphyren derivatives, styryl seriescoloringmatter, tetracene derivatives, pyrazoline derivatives,decacyclene, phenoxazone, and others can be listed.

5. Solvents Used for Forming a Luminous Layer.

When used together with a buffer layer, solvents used for forming aluminous layer is desirable not to dissolve a buffer layer so as toprevent the mixing or dissolving of a buffer layer and materials for aluminous layer and to hold original luminous properties of luminescentmaterials in case of the film formation for the luminous layer.

From this point of view, as a solvent for being applied to a luminouslayer, it is preferable to select such a solvent that the solubility ofmaterials for a buffer layer is 0.001 or less (g/g solvent) at 25° C.under 1 atmospheric pressure, and more preferable to select a solventthat the above-mentioned solubility is 0.0001 or less (g/g solvent).

Further, when plural layers of a luminous layer are applied, solventsused for forming a luminous layer is desirable not to dissolve aphotoresist layer so as to prevent from the mixing or dissolving of thephotoresist layer and materials for a luminous layer and further toprotect a luminous layer that has been already patterned in case of thefilm formation of the second color and after for the luminous layer.

From this point of view, as a solvent for being applied to a luminouslayer, it is preferable to select such a solvent that the solubility ofa photoresist is 0.001 or less (g/g solvent) at 25° C. under 1atmospheric pressure, and more preferable to select a solvent that theabove-mentioned solubility is 0.0001 or less (g/g solvent). For example,in case where a buffer layer dissolves in polar solvents, includingwater series, DMF, DMSO, and alcohol, and a photoresist is a generalpositive resist of novolac series, the following solvents can be listed:aromatic solvents, including each isomer and their mixtures of benzene,toluene and xylene, and each isomer and their mixtures of mesitylene,tetralin, p-cymene, cumene, ethylbenzene, diethylbenzene, butylbenzene,chlorobenzene, and dichlorobenzene; ether solvents, including anisole,phenetole, butylphenyl ether, tetrahydrofuran, 2-butanone, 1,4-dioxane,diethylether, diisopropylether, diphenylether, dibenzylether, anddiglyme; chlorine solvents, including dichloromethane,1,1-dichloroethane, 1,2-dichloroethane, trichloroethylene,tetrachloroethylene, chloroform, carbon tetrachloride, and1-chloronaphthalene; and cyclohexanone and others. However, solventsother than the listed solvents are also usable if they satisfy therequirements, and mixed solvents of two or more may be used.

(When Plural Types of Luminous Layers are Formed)

In the present invention, it is preferable that the above-mentionedluminous layer is a luminous layer in which different types of luminouslayers are formed by the use of the photolithography method in pluraltimes. It is because when the luminous layer is formed in differenttypes of plural luminous layers, full coloring is possible, for example,by selecting red, green, blue and the like.

In this case, for the reasons shown in the following, it is preferablethat a solvent used for forming luminous layers in the above-mentionedluminous layer, which are formed in two times and after, is a poorsolvent to the previously formed luminous layer. Now, the term of “poorsolvent” in the present invention means a solvent having a smallcapacity of dissolving a solute.

That is, when paint for forming a luminous layer is further applied onan luminous layer that has previously been formed (in the following, maybe referred to as a previously formed luminous layer) to form a luminouslayer, because a resist layer is normally formed on the previouslyformed luminous layer, the paint for forming a luminous layer does notcontact the previously formed luminous layer completely. However, sincethe edge parts of the previously formed luminous layer are normally notcovered with the resist layer, the paint for forming a luminous layercontacts the previously formed luminous layer at these points. In caseof contact like this, when the previously formed luminous layer easilydissolves in a solvent contained in the paint for forming a luminouslayer, the luminescent material of the previously formed luminous layerwill dissolve in the paint for forming a luminous layer to cause a colormixture. The present invention has been made to solve problems likethis, and has solved the above-mentioned problem by the use of a poorsolvent to the previously formed luminous layer as a solvent for forminga luminous layer.

FIG. 2 shows an example of production methods of an EL element in thepresent invention. In this example, first, as shown in FIG. 2 (a), thefirst patterned electrode layer 12 and buffer layer 13 are formed onsubstrate 11. This buffer layer will be described in detail later.

And paint for forming the first luminous layer is applied wholly onthese by the use of a spin coating method and the like. This paint forforming the first luminous layer is comprised of at least a luminescentmaterial emitting a light of the first color and a solvent, and of adoping agent and others that are added as needed. The paint for formingthe first luminous layer wholly applied is dried and cured to form thefirst luminous layer 14 (FIG. 2 (a)).

Next, positive resist is applied wholly on the first luminous layer 14to form positive resist layer 15 (FIG. 2 (b)), which positive layer isthen subjected to the pattern exposure of ultraviolet 17 with the use ofphotomask 16 so as not to expose the part that will form the firstluminous layer 14 (FIG. 2 (c)) And the exposed part of positive resistlayer 15 is developed with a developing solution and washed with waterto remove positive resist layer 15 on the exposed part as shown in FIG.2 (d). And by being developed with a developing solution for a luminouslayer, only the first luminous layer 14 on the part not covered withpositive resist layer 15 is removed, remaining positive resist layer 15and the first luminous layer 14 covered with the layer 15 (FIG. 2 (e))Moreover, the development of the luminous layer at this time can becarried out with the use of dry etching as described later.

Next, paint for forming the second luminous layer is applied wholly onthese by the use of a spin coating method and the like (FIG. 2 (f)).Similarly to the above-mentioned paint for forming the first luminouslayer, this paint for forming the second luminous layer is alsocomprised of a luminescent material and a solvent, and further of adoping agent and others that are added as needed. However, a solvent forforming a luminous layer that is used in the second luminous layer isselected to be a poor solvent to the first luminous layer.

On this occasion, as clearly seen from FIG. 2 (f), there are yieldedparts where the above-mentioned wholly applied paint for forming thesecond luminous layer and the first luminous layer 14 are contacted.That is, as mentioned above, the surface of the first luminous layer 14remaining on the substrate 11 is covered with positive resist layer 15,the edge part “a” that has been developed with a luminous layerdeveloping solution is in an exposed state. Consequently, when theabove-mentioned paint for forming the second luminous layer is applied,the first luminous layer 14 and the paint for forming the secondluminous layer are contacted at this edge part “a”. On this occasion,since the paint for forming the second luminous layer is using such asolvent for forming a luminous layer as to be a poor solvent to thefirst luminous layer, the amount that the first luminous layer,especially luminescent materials are eluted into the above-mentionedsolvent for forming the second luminous layer is extremely small.

And, though the second luminous layer 18 is formed by drying andsolidifying the above-mentioned paint for forming the second luminouslayer, the eluted amount of the component of the first luminous layer14, especially the luminescent materials of the first luminous layer 14within the second luminous layer 18 is extremely small, so it ispossible to extremely lower the possibility of occurring problems likecolor mixture and the like in the second luminous layer 18.

Next, as shown in FIG. 2 (g), positive resist layer 15 is formed on thewhole surface, and as shown in FIG. 2 (h), photomask 16 is arranged soas to mask parts where the first and the second luminous layer areformed, and then the surface is exposed with ultraviolet 17. And theexposed surface is developed with a resist developing solution andwashed with water to remove other parts except for positive resistlayers on the parts where the first and the second luminous layer are tobe formed. After that, the exposed second luminous layer is removed withthe second luminous layer developing solution. On this occasion, in thesecond luminous layer developing solution, a solvent that is a poorsolvent to the first luminous layer is selected and used. This isbecause it is possible to avoid problems of color mixture and the likeby the use of a poor solvent to the first luminous layer as a solvent inthe above-mentioned second luminous layer developing solution, since thesecond luminous layer developing solution and the first luminous layerare contacted at the edge part “a” in the above-mentioned first luminouslayer when the second luminous layer is developed.

By being developed with the second luminous layer developing solution,as shown in FIG. 2 (i), only the second luminous layer 18 on the partwhere positive resist layer 15 has not been remained is removed, andonly the part covered with positive resist layer 15 is remained.Further, in the developing process of the second luminous layer 18, itis possible to use a dry etching method that will be described later.

Moreover, similarly to the formation of the first and the secondluminous layer, paint for forming the third luminous layer is applied onthe whole surface by the use of a spin coating method and the like.Similarly to the above-mentioned paint for forming the first and thesecond luminous layer, the paint for forming the third luminous layer atthis time is also comprised of a luminescent material and a solvent, andfurther of a doping agent that is added as needed and others. Further, asolvent for forming the third luminous layer that is used at this timeis selected to be a poor solvent to the above-mentioned first luminouslayer 14 and the second luminous layer 18.

When the paint for forming the third luminous layer was applied, forexample, as shown in FIG. 2 (j), the applied paint for forming the thirdluminous layer contacts the first luminous layer at the edge part “a” ofthe first luminous layer 14 that was first formed and further contactsthe second luminous layer at the edge part “b” and the edge part “c” ofthe second luminous layer 18. At this time, similarly, since the solventfor forming the third luminous layer becomes a poor solvent to the firstluminous layer 14 and the second luminous layer 18, the amount that theabove-mentioned first luminous layer 14 and the second luminous layer 18are eluted into the paint for forming the third luminous layer becomesextremely small. Consequently, after this, when the paint for formingthe third luminous layer is dried and solidified to form the thirdluminous layer 19, such problems as color mixture and the like will notbe yielded in the third luminous layer 19.

Next, positive resist layer 15 is formed whole on the third luminouslayer 19 (FIG. 2 (j)). And, as shown in FIG. 2 (k), photomask 16 isarranged so as to mask parts where the first, the second and the thirdluminous layer are formed, and then the surface is exposed withultraviolet 17. This is developed with a resist developing solution andwashed with water. And, though the development is carried out with theuse of the third luminous layer developing solution, at this time,similarly, in the third luminous layer developing solution, a solventthat becomes a poor solvent to the above-mentioned first luminous layer14 and the second luminous layer 18, especially to each luminescentmaterial is selected and used. Consequently, also in this developingprocess of the third luminous layer, it is not possible that the firstluminous layer 14 and/or the second luminous layer 18, especially theirluminescent materials elute in the developing solution to causetroubles, including color mixture.

Through the development of the third luminous layer 19 with the thirdluminous layer developing solution like this, as shown in FIG. 2 (l),only the third luminous layer 19 on the part not covered with positiveresist layer 15 is removed, and other parts covered with positive resistlayer 15 are remained.

And, upper layers on the part where the resist is formed are peeled offthrough peeling treatment with a resist peeling liquid, and as shown inFIG. 2 (m), bare three colored luminous layers of the first luminouslayer 14 (normally blue), the second luminous layer 18 (normally green),and the third luminous layer 19 (normally red) are formed. Lastly, asshown in FIG. 2 (n), the second electrode layer 20 is formed on theseluminous layers to produce an EL element that emits EL light emission 21downward in the figure.

In the present invention, the term of poor solvent indicates a solventfor forming a luminous layer of the luminous layers formed in the secondtime and after that the solubility of materials constituting apreviously formed luminous layer is 0.1 g/g solvent or less at 25° C.under 1 atmospheric pressure. Especially in the present invention, theabove-mentioned solubility is preferable to be 0.05 g/g solvent or less.

It is because if the solubility is in this degree, when materialsconstituting a previously formed luminous layer dissolve in a solventfor forming a luminous layer of a new luminous layer to be formed andthe materials constituting the previously formed luminous layer aremixed into the newly formed luminous layer, the amount is extremelysmall, there will be no trouble like color mixture.

Moreover, in the present invention, when luminous layers are formed inplural times by a photolithography method, these plural luminous layersare preferable to be formed in the order of the short wavelength siderelative to the wavelength of light obtained from each luminous layer.The reasons are as follows:

That is, usually, when two or more colors are mixed, the excitationenergy is moved from an exciton in a high level to an exciton in a lowlevel in a fluorescent luminescent material, and fluorescence from thelowest excitation state is observed. In other words, when a shorterwavelength luminescent component with high energy and a long wavelengthluminescent component with low energy are mixed, luminescence from thelong-wavelength luminescent component becomes to constitute the mainpart of luminescence. The present invention utilizes such a property ofa luminescent material, and through forming luminous layers in the orderof the short wavelength of light emitted from them, the second luminouslayer formed with a long wavelength luminescent material is formed onthe first luminous layer previously formed with a short wavelengthluminescent material. Consequently, when the film of the second luminouslayer is formed on a substrate where the above-mentioned first luminouslayer has been patterned, even if part of the luminescent materialelutes from the edge part of the patterned first luminous layer andmixes into the second luminous layer, the excitation energy of theluminescent material in the first luminous layer moves and onlyluminescence from the second luminous layer is observed. As a result, itis possible to minimize the lowering of luminescent properties.

This point will be further described with reference to theabove-mentioned FIG. 2. The descriptions from FIG. 2 (a) to FIG. 2 (e)will be omitted here because they are the same as the above-mentioneddescriptions. In FIG. 2 (f), paint for forming the second luminous layeris applied on the whole surface by the use of a spin coating method andthe like. The paint for forming the second luminous layer to be used atthis time is comprised of, similarly to the paint for forming the firstluminous layer as mentioned above, a luminescent material and a solvent,and further of a doping agent and others that are added as needed,however the luminescent material is selected so that the wavelength oflight emitted from the luminescent material used in the second luminouslayer is longer than that of light emitted from the luminescent materialused in the above-mentioned first luminous layer.

At this time, clearly seen from FIG. 2 (f), there is produced part wherethe above-mentioned paint for forming the second luminous layer appliedon the whole surface and the first luminous layer 14 are contacted. Thatis, though the surface of the first luminous layer 14 remained on thesubstrate 11 is covered with positive resist layer 15 as mentionedabove, the edge part “a” that has been developed with a luminous layerdeveloping solution is in a exposed state. Consequently, when theabove-mentioned paint for forming the second luminous layer is appliedon this, the first luminous layer 14 and the paint for forming thesecond luminous layer are contacted at the edge part “a”. At this time,since the paint for forming the second luminous layer contains a solventas mentioned above, though depending upon the solubility of this solventand the luminescent material contained in the first luminous layer, apart of the luminescent material in the first luminous layer may beeluted in the above-mentioned paint for forming the second luminouslayer. If the second luminous layer 18 is formed by drying andsolidifying in the state that the luminescent material of the firstluminous layer is eluted in the paint for forming the second luminouslayer, the second luminous layer 18 will contain the luminescentmaterial in the first luminous layer. However, in this example, sincethe luminescent material in the first luminous layer and luminescentmaterial in the second luminous layer are selected on the basis asmentioned above, that is, the wavelength of the light emitted from theluminescent material of the first luminous layer will be shorter thanthat of the light emitted from the luminescent material of the secondluminous layer, even if the luminescent material of the first luminouslayer is mixed in the second luminous layer, for the above-mentionedreason, it is possible to lower the possibility of light emission fromthe luminescent material of the first luminous layer in the secondluminous layer.

After that, about FIG. 2 (g) and FIG. 2 (i), the same process as theabove description will be performed. And, similarly to the formation ofthe first and second luminous layers, paint for forming the thirdluminous layer is applied on the whole surface with the use of a spincoating method and the like. Similarly to the above-mentioned paints forforming the first and second luminous layers, the paint for forming thethird luminous layer at this time has also a luminescent material and asolvent, and further a doping agent that is added as needed. Andluminescent materials to be used at this time are selected so that thewavelength of the fluorescence from the luminescent material used in thethird luminous layer will be longer than that of the luminescence fromthe luminescent material used in the above-mentioned first luminouslayer and the above-mentioned second luminous layer.

Like this, when paint for forming the third luminous layer is applied,for example, as shown in FIG. 2 (j), the applied paint for forming thethird luminous layer is contacted with the first luminous layer at theedge part “a” of the first luminous layer 14 that was formed for thefirst time, and further with the second luminous layer at the edge part“b” and the edge part “c” of the second luminous layer 18. At this time,it is also possible that the luminescent material in the first luminouslayer and the luminescent material in the second luminous layer dissolvein the solvent in the paint for forming the third luminous layer toelute in the paint for forming the third luminous layer. Also in thiscase, because the luminescent material in the above-mentioned thirdluminous layer is selected so that the wavelength of the fluorescenceemitted from the luminescent material will be longer than that of theluminescence emitted from the luminescent material in the first luminouslayer and the luminescent material in the second luminous layer, for theabove-mentioned reason, there is a low possibility that the luminescentmaterial of the first luminous layer and the luminescent material of thesecond luminous layer emit light within the third luminous layer,resulting in decreasing the anxiety of causing color mixture.

In the present invention, it is preferable to apply luminescentmaterials for forming luminous layers in the order of the shortwavelength of the light emitted from them. To be concrete, usually inorder to obtain a full color image, luminescent materials to emit redfluorescence, green fluorescence, and further blue fluorescence are usedas luminescent materials, however when these luminescent materials areused, it is preferable that luminous layers containing these luminescentmaterials are applied and formed so that these luminescent materials arein the order of the short wavelength, that is, in blue color, greencolor, and red color order.

Here, as luminescent materials to emit blue fluorescence that can beused in the present invention, distyrylbenzene derivatives, oxadiazolderivatives, and their polymers, polyvinylcarbazole derivatives,polyparaphenylene derivatives, polyfluorene derivatives, and others canbe listed. Among them, polymer materials of polyvinylcarbazolederivatives, polyparaphenylene derivatives, polyfluorene derivatives,and others are preferable, however not especially limited to them.

And, as luminescent materials to emit green fluorescence, quinacridonderivatives, coumarin derivatives, and their polymers, polyparaphenylenevinylene derivatives, polyfluorene derivatives, and others can belisted. Among them, polymer materials of polyparaphenylene vinylenederivatives, polyfluorene derivatives, and others are preferable,however not especially limited to them.

Further, as luminescent materials to emit red fluorescence, coumarinderivatives, thiophene cyclic compounds and their polymers,polyparaphenylene vinylene derivatives, polythiophene derivatives,polyfluorene derivatives, and others can be listed. Among them, polymermaterials of polyparaphenylene vinylene derivatives, polythiophenederivatives, polyfluorene derivatives, and others are preferable,however not especially limited to them.

(Other Organic EL Layers)

1. Electric Charge Transporting Layer

As an organic EL layer in the present invention, an electric chargeinjection layer can also be listed. The electric charge injection layerincludes a positive hole injection layer and an electron injectionlayer. They are not especially limited as long as they are generallyused in EL elements as those described in, for example, Japanese PatentApplication Laid-Open No. 11-4011.

Moreover, a luminescent material, a positive hole transporting material,or an electron transporting material constituting the above-mentionedlayer may be used independently each or in a mixture. The same materialmay be contained either in one layer or in plural layers.

2. Electrode Layer

In the present invention, an electrode layer is generally not limited aslong as it is used in an EL element, and an electrode layer firstprovided on a substrate may be referred to as the first electrode layerand an electrode layer provided after forming an organic EL layer as thesecond electrode layer. These electrode layers are comprised of an anodeand a cathode, one of which is transparent or semitransparent, and theanode is preferable to be a conductive material having a large workfunction so that positive holes are easily injected. Moreover, pluralmaterials may be mixed in these electrodes. Both electrode layers arepreferable to have as low resistance as possible. Generally, metalmaterials are used, however organic materials or inorganic materials maybe used.

As preferable anode materials, for example, ITO, iridium oxide, and goldare listed. As preferable cathode materials, for example, magnesiumalloys (MgAg and others), aluminum alloys (AlLi, AlCa, AlMg and others),calcium metal, and metals having low work functions are listed.

3. Insulation Layer

In the EL element of the present invention, in order to cover thepatterned edge part of the first electrode layer formed on the substrateand the non-luminous part of the element to prevent a short at the partunnecessary for luminescence, an insulation layer may be provided inadvance so that the luminous part will be open. Thus, it is possible toobtain an element with a long life and stable luminescence by decreasingthe defects due to the short of elements and the like.

As generally known, for example, it is possible to form a pattern ofabout 1 μm in thickness with the use of an ultraviolet curing resinmaterial and the like, however when an organic EL layer is patterned bythe dry etching of the present invention, the insulation layer ispreferable to be resistant to dry etching. When the resistance is low,it is preferable to form the insulation layer in 1 μm or more, forexample, 1.5 to 10 μm in thickness and to prevent the damage due to dryetching, more preferable to form the layer in 2 to 5 μm in thickness.

B. EL Element.

Next, the EL element of the present invention will be described. The ELelement of the present invention has three embodiments as describedlater, and all of them can be produced by the above-mentioned productionmethod of an EL element. In the following, each embodiment will bedescribed.

First Embodiment

The first embodiment of the EL element of the present invention is an ELelement having at least one patterned organic EL layer, and ischaracterized in that the EL element does not have any of a partition, astructure aiding patterning, and surface treatment aiding patterning.

Though the EL element of the present embodiment has an patterned organicEL layer, it does not have any of a partition, a structure aidingpatterning, and surface treatment aiding patterning. Consequently, ithas an advantage that it is advantageous in respect of cost.

In the present embodiment, the above-mentioned organic EL layer ispreferable to be an EL layer formed by a polymer material, because thelayer cannot be formed by the vapor deposition method. And theabove-mentioned organic EL layer is preferable to be a luminous layer inwhich especially patterning is indispensable.

Concerning other constitutions, the description will be omitted becausethey are the same as those described in the production method of theabove-mentioned EL element.

Second Embodiment

The second embodiment of the EL element of the present invention is anEL element having at least one organic EL layer, the above-mentionedorganic EL layer is a patterned luminous layer and is characterized inthat the width of an area with uneven film thickness formed on the edgepart of the above-mentioned patterned luminous layer is 15 μm or less,preferable 10 μm or less, and especially preferable 7 μm or less. Here,the term of “an area with uneven film thickness” indicates an area thatexists on the edge part and the film thickness is equal to or less than90% of the average film thickness of the flat part.

In the EL element obtained by the above-mentioned production method ofan EL element, the luminous layer that is patterned by thephotolithography method is different from the luminous layer that ispatterned by the inkjet method and others and is highly uniform inthickness, and the shape of an edge on the peripheral area of theluminous layer can be freely controlled by etching conditions.Consequently, it is possible to adjust the width of an edge area, thatis, an area with uneven film thickness to such a shape that the edge isstood straight, that is, the width of the area with uneven filmthickness is narrowed or to such a shape that the edge is made to betaper, that is, the width of the area with uneven film thickness isbroadened.

On the other hand, the area with uneven film thickness of the luminouslayer that is patterned by the conventional inkjet method usually has awidth of more than 15 μm. Consequently, it was difficult to minutelyarrange pixels constituting each color formed by patterning like this.

Here, FIG. 3 shows the area with uneven film thickness, that is, theedge part in the luminous layer of an EL element of the presentinvention, and FIG. 4 shows the area with uneven film thickness in theluminous layer patterned by the conventional inkjet method. As clearlyseen from these figures, the area with uneven film thickness of the edgepart in the luminous layer that is patterned by the conventional inkjetmethod is broad, however the area with uneven film thickness in theluminous layer of the EL element of the present invention isconsiderably narrow.

In the EL element in the present embodiment, because the width of thearea with uneven film thickness of the edge part in the luminous layeris not more than the above-mentioned value, it is possible to make thedistance between each pixel small. Thus, this embodiment has advantagesthat it is possible to arrange each pixel minutely and to make an ELelement by which an image with high quality can be obtained.

In the present embodiment, a material to form a luminous layer ispreferable to be an organic polymer material that cannot be formed bythe vapor deposition method. And, the luminous layer is preferable to beconstituted in at least three layers so that a full color image can beobtained. Further, concerning other constitutions, materials and others,the description will be omitted because they are the same as thosedescribed in the production method of the above-mentioned EL element.

Third Embodiment

The third embodiment of the EL element of the present invention is an ELelement having at least one organic EL layer and characterized in thatthe above-mentioned organic EL layer is a patterned luminous layer thatcan emit light with plural colors and the distance between adjacentluminous layers emitting light with different color is 30 μm or less,preferable 20 μm or less, and especially preferable 15 μm or less.

Further, here the distance between luminous layers indicates the spacebetween pixels consisting of each patterned luminous layer.

In the inkjet method that is the most well known wet patterning methodfor a luminous layer, it is general to prepare usually the distancebetween patterned luminous layers of at least 40 μm or more, because thefilm uniformity is low at the edge part, the adhered position of jettedink is unstable, and because it is necessary to prepare ink-repellentbanks or to form ink-repellent patterns in order to define the rangewhere ink wet and spread, and others. Consequently, it is impossible tocarry out the patterning of an element with small pixel pitch like, forexample, 42 μm or less.

On the other hand, the EL element in the present embodiment is an ELelement that a high molecular weight or low molecular weight luminouslayer can be produced by wet film formation, the patterning accuracy ofthe luminous layer is high, and because the edge part of the patternedluminous layer is different from the edge that is formed by drying andis formed using the technique of removing unnecessary parts bydissolving or etching, the film uniformity in the luminous layer is highand there is only a inclined area of, for example, about 5 μm from thepatterned end. Consequently, when a full color display is manufactured,each distance between pixels of luminescence parts can be made to besmall, it is thus possible to make the active area ratio large. Further,since the distance between pixels can be made to be small, it ispossible to arrange each pixel minutely.

In the present embodiment similarly to the second embodiment, a materialto form a luminous layer is preferable to be an organic polymer materialthat cannot be formed by the vapor deposition method. And, the luminouslayer is preferable to be constituted in at least three layers so that afull color image can be obtained. Further, concerning otherconstitutions, materials and others, the description will be omittedbecause they are the same as those described in the production method ofthe above-mentioned EL element.

(Others)

In EL elements shown in the above-mentioned first, second and thirdembodiments, the element is preferable to be made in a constitutionhaving at least a substrate, an electrode layer formed in a patternshape on the above-mentioned substrate, and an insulation layer coveringthe edge part of the above-mentioned electrode layer and the nonluminouspart of the element.

It is because defects due to the short of elements and the like can bedecreased as mentioned above by covering the edge part of the electrodelayer formed in such a pattern shape with an insulation layer.

As a substrate to be used here, as long as such a substrate of glass andthe like as is usually used in an EL element is used, it is notespecially limited.

Further, concerning an electrode layer and an insulation layer, thedescription will be omitted because they are the same as those describedin the column of the production method of the above-mentioned ELelement.

(Concrete Combinations of Materials)

Suitable combinations of materials with which the patterning of the ELelement in the present invention can be carried out utilizing theirsolubility in the above-mentioned specific solvents are, for example, asfollows:

Buffer layer: Polyalkylthiophene derivatives, polyaniline derivatives.

Luminous layer: Polyparaphenylene vinylene derivatives, polyfluorenederivatives, polyvinylcarbazole derivatives.

Photoresist: Positive photoresist (novolac resins).

Photoresist solvent: Cellosolve, cellosolve acetate.

Photoresist developing solution: Organic alkali developing solution.

Photoresist peeling liquid: Cellosolve, cellosolve acetate, acetone.

Solvent for forming a luminous layer: Xylene, toluene.

On the other hand, even though generally used EL element materials andphotoresist materials are used, for example, the following combinationsare not suitable in the present invention (however, each material may bea suitable material in combination with other materials.)

Buffer layer: Polyalkylthiophene derivatives, polyaniline derivatives.

Luminous layer: TPD/Alq3 having the following structure,polyvinylcarbazole+oxadiazole derivatives+fluorescent coloring matter.

Photoresist: Positive photoresist (novolac resins).

Photoresist solvent: Cellosolve, cellosolve acetate.

Photoresist developing solution: Organic alkali developing solution.

Photoresist peeling liquid: Cellosolve, cellosolve acetate, acetone.

Solvent for forming a luminous layer: Dichloroethane (in case ofTPD/Alq3, vacuum film formation.)

In the present invention, it is unsuitable to use the combination ofpolyvinylcarbazole+an oxadiazole derivative+fluorescent coloring matterin a luminous layer because the oxadiazole derivative and thefluorescent coloring matter will elute when the resist film is formedand peeled off. Further, it is also unsuitable to use TPD/Alq3 in aluminous layer because TPD and Alq3 elute when the resist film is formedand peeled off, TPD crystallizes by the heating process ofphotolithography, and other reasons.

Moreover, the present invention is not limited in the above-mentionedembodiments. The above-mentioned embodiments are illustrations. Allmodifications that have substantially the same constitutions astechnical thoughts described in the claims of the present invention andtake the same effects should be included in the technical scope of thepresent invention.

EXAMPLES

In the following, examples will be shown and the present invention willbe further described.

Example 1 When a Luminous Layer is Made in a Single Layer

(Patterning of a Buffer Layer)

A patterned ITO substrate of 3 inches square and 1.1 mm in thickness waswashed and used in this example as a substrate and the first electrodelayer.

The spin coating of the substrate was carried out by dropping 0.5 ml ofa coating liquid for a buffer layer shown in the following chemicalformula (1) (poly-3,4-ethylenedioxythiophene/polystyrenesulphonate(PEDT/PSS): made by Bayer AG (Baytron P)) in the center part of thesubstrate.

A buffer layer was formed by holding the spin coated substrate at 2500rpm for 20 seconds, and then the buffer layer was dried at 150° C. for 5minutes. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A resist layer was formed byholding the spin coated substrate at 500 rpm for 10 seconds and thenholding at 2000 rpm for 20 seconds. As a result, the film thicknessbecame about 1 μm. The resist layer was prebaked at 80° C. for 30minutes. After that, the layer was set together with an exposure mask inan alignment exposure device and the part where the buffer layer shouldbe removed was exposed to ultra violet light. The exposed layer wasdeveloped with a resist developing solution (NMD-3 made by Tokyo OhkaKogyo Co., Ltd.) for 20 seconds, and then washed with water to removethe photoresist and buffer layers of the exposed part. After being postbaked at 120° C. for 30 minutes, all of the photoresist were removedwith acetone and the buffer layer that is insoluble in acetone wasformed in an optional pattern.

(Patterning of a Luminous Layer)

The spin coating of the substrate where the buffer layer had beenpatterned was carried out by dropping 2 ml of a 1 wt % xylene solutionof luminescent polymer MEH-PPV, which is a polyparaphenylene vinylenederivative and shown in the following chemical formula (2), in thecenter part of the substrate.

A luminous layer was formed by holding the spin coated substrate at 2000rpm for 10 seconds, and then the luminous layer was dried at 80° C. for1 hour. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A resist layer was formed byholding the spin coated substrate at 500 rpm for 10 seconds and thenholding at 2000 rpm for 20 seconds. As a result, the film thicknessbecame about 1 μm. The resist layer was prebaked at 80° C. for 30minutes. After that, the layer was set together with an exposure mask inan alignment exposure device and the part where the luminous layershould be removed was exposed to ultra violet light. The exposed layerwas developed with a resist developing solution (NMD-3 made by TokyoOhka Kogyo Co., Ltd.) for 20 seconds, and then washed with water toremove the photoresist of the exposed part. After being post baked at90° C. for 30 minutes, the luminous layer on the part where thephotoresist had been removed was removed with toluene. All of thephotoresist were removed with acetone and the luminous layer that isinsoluble in acetone was formed in an optional pattern.

On the substrate obtained after drying at 90° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

Though the resolution of the obtained pattern depends on the resolvingpower of the positive resist, the resolution of 10 μm, which isimpossible by the conventional methods of the vapor deposition maskmethod and the inkjet method, and the highly fine lines could be formedin this example.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode (the first electrode) side and Ag electrode (the secondelectrode) side were connected to an anode and a cathode, respectively,and were applied with direct current from a source meter. When 10V wasapplied, luminescence was observed, and it was evaluated that there wasno deterioration in the voltage of starting luminescence due topatterning with the use of the photolithography method. And no loweringwas observed in the luminescence efficiency. Further, because of thepatterning of the buffer layer, insulation properties between anodelines can be improved, resulting in the decrease in the incidence rateof crosstalk.

Example 2 When a Luminous Layer is Made in Three Layers

A buffer layer was patterned similarly to Example 1.

The spin coating of the substrate where a buffer layer had beenpatterned was carried out as the first luminous layer by dropping 2 mlof a 1 wt % xylene solution of luminescent polymer MEH-PPV, which is apolyparaphenylene vinylene derivative, in the center part of thesubstrate. A luminous layer was formed by holding the spin coatedsubstrate at 2000 rpm for 10 seconds. As a result, the film thicknessbecame 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A resist layer was formed byholding the spin coated substrate at 500 rpm for 10 seconds and thenholding at 2000 rpm for 20 seconds. As a result, the film thicknessbecame about 1 μm. The resist layer was prebaked at 80° C. for 30minutes. After that, the layer was set together with an exposure mask inan alignment exposure device and the part where the luminous layershould be removed except the luminous part of the first color wasexposed to ultraviolet light. The exposed layer was developed with aresist developing solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.)for 20 seconds, and then washed with water to remove the photoresist ofthe exposed part. After being post baked at 90° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with toluene. A substrate in which the first luminous part wasprotected with the photoresist and the buffer layer of the second andthird luminous parts was exposed was obtained.

The spin coating of the substrate was carried out as the second luminouslayer by dropping 2 ml of a 1 wt % xylene solution of luminescentpolymer MEH-PPV, which is a polyparaphenylene vinylene derivative, inthe center part of the substrate. A luminous layer was formed by holdingthe spin coated substrate at 2000 rpm for 10 seconds. As a result, thefilm thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A resist layer was formed byholding the spin coated substrate at 500 rpm for 10 seconds and thenholding at 2000 rpm for 20 seconds. As a result, the film thicknessbecame about 1 μm. The resist layer was prebaked at 80° C. for 30minutes. After that, the layer was set together with an exposure mask inan alignment exposure device and the part where the luminous layershould be removed except the first and second luminous parts was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part. After being post baked at 90° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with toluene. A substrate in which the first and second luminousparts were protected with the photoresist and the buffer layer of thethird luminous part was exposed was obtained.

The spin coating of the substrate was carried out as the third luminouslayer by dropping 2 ml of a 1 wt % xylene solution of luminescentpolymer MEH-PPV, which is a polyparaphenylene vinylene derivative, inthe center part of the substrate. A luminous layer was formed by holdingthe spin coated substrate at 2000 rpm for 10 seconds. As a result, thefilm thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A resist layer was formed byholding the spin coated substrate at 500 rpm for 10 seconds and thenholding at 2000 rpm for 20 seconds. As a result, the film thicknessbecame about 1 μm. The resist layer was prebaked at 80° C. for 30minutes. After that, the layer was set together with an exposure mask inan alignment exposure device and the part where the luminous layershould be removed except the first to third luminous parts was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part. After being post baked at 90° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with toluene. A substrate in which the first to third luminousparts were protected with the photoresist was obtained. After that, allof the photoresist were removed with acetone.

On the substrate obtained after drying at 90° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

Though the resolution of the obtained pattern depends on the resolvingpower of the positive resist, the resolution of 10 μm, which isimpossible by the conventional methods of the vapor deposition maskmethod and the inkjet method, and the highly fine lines could be formedin this example.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode (the first electrode) side and Ag electrode (the secondelectrode) side were connected to an anode and a cathode, respectively,and were applied with direct current from a source meter. When 10 V wasapplied, luminescence was observed from each of the first to thirdluminous parts, and it was evaluated that there was no deterioration inthe voltage of starting luminescence due to patterning with the use ofthe photolithography method. And no lowering was observed in theluminescence efficiency. Further, because of the patterning of thebuffer layer, insulation properties between anode lines can be improved,resulting in the decrease in the incidence rate of crosstalk.

Example 3 The Change of the Solvent

An EL element was manufactured in the same way as Example 1 except thatpolyvinylcarbazole shown by the following chemical formula (3) was usedas a luminous layer and toluene as a solvent for the luminous layer.

Though the resolution of the obtained pattern depends on the resolvingpower of the positive resist, the resolution of 10 μm, which isimpossible by the conventional methods of the vapor deposition maskmethod and the inkjet method, and the highly fine lines could be formedin this example.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode (the first electrode) side and Ag electrode (the secondelectrode) side were connected to an anode and a cathode, respectively,and were applied with direct current from a source meter. When 15V wasapplied, luminescence was observed, and it was evaluated that there wasno deterioration in the voltage of starting luminescence due topatterning with the use of the photolithography method. And no loweringwas observed in the luminescence efficiency. Further, because of thepatterning of the buffer layer, insulation properties between anodelines can be improved, resulting in the decrease in the incidence rateof crosstalk.

Example 4 Patterning by Dry Etching

(The Film Formation of a Buffer Layer.)

A patterned ITO substrate of 3 inches square and 1.1 mm in thickness waswashed and used in this example as a substrate and the first electrodelayer. The spin coating of the substrate was carried out by dropping 0.5ml of a coating liquid for a buffer layer (Baytron P made by Bayer AG,and shown in the above chemical formula (1)) in the center part of thesubstrate. A layer was formed by holding the spin coated substrate at2500 rpm for 20 seconds. As a result, the film thickness became 800 Å.

(Patterning of a Luminous Layer)

The spin coating of the substrate where the buffer layer had beenpatterned was carried out by dropping 2 ml of a 1 wt % xylene solutionof luminescent polymer MEH-PPV, which is a polyparaphenylene vinylenederivative, in the center part of the substrate. A layer was formed byholding the spin coated substrate at 2000 rpm for 10 seconds. As aresult, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed wasexposed to ultraviolet light. The exposed layer was developed with aresist developing solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.)for 20 seconds, and then washed with water to remove the photoresist ofthe exposed part.

After being post baked at 120° C. for 30 minutes, the substrate wassubjected to oxygen plasma treatment at a pressure of 150 millitorrs andwith 150 W power for 20 minutes. Since the photoresist layer is 5 timesor more thicker than the buffer layer and the luminous layer, only theluminous and buffer layers on the part that had not been protected withthe photoresist were peeled off and ITO electrode was bared. A substratehaving the first luminous part protected with the photoresist wasobtained.

A coating liquid for a buffer layer was spin coated on the obtainedsubstrate and a buffer layer of 800 Å was obtained. Then, the spincoating of the substrate was carried out as the second luminous layer bydropping 2 ml of a 1 wt % xylene solution of luminescent polymerMEH-PPV, which is a polyparaphenylene vinylene derivative, in the centerpart of the substrate. A layer was formed by holding the spin coatedsubstrate at 2000 rpm for 10 seconds. As a result, the film thicknessbecame 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous part of the first and second colors was exposed toultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part.

After being post baked at 120° C. for 30 minutes, the substrate wassubjected to oxygen plasma treatment at a pressure of 150 millitorrs andwith 150 W power for 20 minutes. Since the photoresist layer is 5 timesor more thicker than the buffer layer and the luminous layer, only theluminous and buffer layers on the part that had not been protected withthe photoresist were peeled off and ITO electrode was bared. A substratehaving the first and second luminous parts protected with thephotoresist was obtained.

A coating liquid for a buffer layer was spin coated on the obtainedsubstrate and a buffer layer of 800 Å was obtained. Then, the spincoating of the substrate was carried out as the third luminous layer bydropping 2 ml of a 1 wt % xylene solution of luminescent polymerMEH-PPV, which is a polyparaphenylene vinylene derivative, in the centerpart of the substrate. A layer was formed by holding the spin coatedsubstrate at 2000 rpm for 10 seconds. As a result, the film thicknessbecame 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous part of the first to third colors was exposed toultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part.

After being post baked at 120° C. for 30 minutes, the substrate wassubjected to oxygen plasma treatment at a pressure of 150 millilitersand with 150 W power for 20 minutes. Since the photoresist layer is 5times or more thicker than the buffer layer and the luminous layer, onlythe luminous and buffer layers on the part that had not been protectedwith the photoresist were peeled off. A substrate having the first tothird luminous parts protected with the photoresist was obtained. Afterthat, all of the photoresist were removed with acetone.

On the substrate obtained after drying at 100° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode side and Ag electrode side were connected to a positiveelectrode and a negative electrode, respectively, and were applied withdirect current from a source meter. When 10 V was applied, luminescencewas observed from each of the first to third luminous parts.

Example 5 The Use of Atmospheric Plasma

An EL element was manufactured in the same way as Example 4 except forthe use of atmospheric-pressure plasma instead of oxygen plasmatreatment. Similarly to Example 4, the pattern could be formed, andluminescence was observed from each of the first to third luminousparts.

Example 6 The Use of an Ultrasonic Bath

(The Film Formation of a Buffer Layer.)

A patterned ITO substrate of 6 inches square and 1.1 mm in thickness waswashed and used as a substrate and the first electrode layer. The spincoating of the substrate was carried out by dropping 0.5 ml of a coatingliquid for a buffer layer (Baytron P made by Bayer AG, and shown in theabove chemical formula (1)) in the center part of the substrate. A layerwas formed by holding the spin coated substrate at 2500 rpm for 20seconds. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the buffer layer should be removed was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist and bufferlayers of the exposed part. After being post baked at 120° C. for 30minutes, all of the photoresist were removed with acetone and the bufferlayer that is insoluble in acetone was formed in an optional pattern.

(The Film Formation of a Luminous Layer)

The spin coating of the substrate where the buffer layer had beenpatterned was carried out as the first luminous layer by dropping 2 mlof a 1 wt % xylene solution of luminescent polymer MEH-PPV, which is apolyparaphenylene vinylene derivative, in the center part of thesubstrate. A layer was formed by holding the spin coated substrate at2000 rpm for 10 seconds. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous part of the first color was exposed to ultraviolet light.The exposed layer was developed with a resist developing solution (NMD-3made by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, and then washed withwater to remove the photoresist of the exposed part. After being postbaked at 120° C. for 30 minutes, the luminous layer on the part wherethe photoresist had been removed was removed with toluene in anultrasonic bath. A substrate in which the first luminous part wasprotected with the photoresist was obtained.

The spin coating of the substrate was carried out as the second luminouslayer by dropping 2 ml of a 1 wt % xylene solution of luminescentpolymer MEH-PPV, which is a polyparaphenylene vinylene derivative, inthe center part of the substrate. A layer was formed by holding the spincoated substrate at 2000 rpm for 10 seconds. As a result, the filmthickness became 800 Å. The second luminous layer was peeled offtogether with the photoresist formed on the upper part of the patternedfirst luminous layer by peeling off the photoresist with acetone to makethe patterned first luminous layer expose.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous parts of the first and the second color was exposed toultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part. After being post baked at 120° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with toluene in an ultrasonic bath. A substrate in which thefirst and second luminous parts were protected with the photoresist wasobtained.

The spin coating of the substrate was carried out as the third luminouslayer by dropping 2 ml of a 1 wt % xylene solution of luminescentpolymer MEH-PPV, which is a polyparaphenylene vinylene derivative, inthe center part of the substrate. A layer was formed by holding the spincoated substrate at 2000 rpm for 10 seconds. As a result, the filmthickness became 800 Å. The third luminous layer was peeled off togetherwith the photoresist formed on the upper parts of the patterned firstand second luminous layers by peeling off the photoresist with acetoneto make the patterned first and second luminous layers expose.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe first to third luminous parts was exposed to ultraviolet light. Theexposed layer was developed with a resist developing solution (NMD-3made by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, and then washed withwater to remove the photoresist of the exposed part. After being postbaked at 120° C. for 30 minutes, the luminous layer on the part wherethe photoresist had been removed was removed with toluene in anultrasonic bath. A substrate in which the first to third luminous partswere protected with the photoresist was obtained. After that, all of thephotoresist were removed with acetone to make the patterned luminouslayer expose.

On the substrate obtained after drying at 100° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode side and Ag electrode side were connected to a positiveelectrode and a negative electrode, respectively, and were applied withdirect current from a source meter. When 10 V was applied, luminescencewas observed from each of the first to third luminous parts.

Example 7 The Formation of an Insulation Layer

A patterned ITO substrate of 3 inches square and 1.1 mm in thickness waswashed and used as a substrate and the first electrode layer. At thistime, the pattern in the ITO substrate was 84 μm in line and 16 μm inspace. On the above space part and the edge parts (5 μm each) of the ITOsubstrate, an insulation layer of 5 μm in thickness was formed in thewidth of 26 μm with the use of negative resist comprising of aninsulative ultraviolet curing type resin. An EL element was thus formedsimilarly to Example 4 as far as others are concerned.

After patterning for forming the first, second and third luminouslayers, the insulation layer fulfills its function as an insulationlayer without being broken down and luminescence was observed from eachof the first to third luminous parts. Thus, it was found that if aninsulation layer was formed, it was possible to form a pattern similarlyto the case of Example 4.

Example 8 A Solvent for a Luminous Layer

(The Film Formation of a Buffer Layer.)

A patterned ITO substrate of 6 inches square and 1.1 mm in thickness waswashed and used as a substrate and the first electrode layer. The spincoating of the substrate was carried out by dropping 0.5 ml of a coatingliquid for a buffer layer (Baytron P made by Bayer AG, and shown in theabove chemical formula (1)) in the center part of the substrate. A layerwas formed by holding the spin coated substrate at 2500 rpm for 20seconds. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the buffer layer should be removed was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist and bufferlayers of the exposed part. After being post baked at 120° C. for 30minutes, all of the photoresist were removed with acetone and the bufferlayer that is insoluble in acetone was formed in an optional pattern.

(The Film Formation of a Luminous Layer)

The spin coating of the substrate where the buffer layer had beenpatterned was carried out as the first luminous layer by dropping 2 mlof a 2 wt % toluene solution of polyvinylcarbazole (shown in the abovechemical formula (3)) in the center part of the substrate. A layer wasformed by holding the spin coated substrate at 2000 rpm for 10 seconds.As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous part of the first luminous layer was exposed to ultravioletlight. The exposed layer was developed with a resist developing solution(NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, and thenwashed with water to remove the photoresist of the exposed part. Afterbeing post baked at 120° C. for 30 minutes, the luminous layer on thepart where the photoresist had been removed was removed with toluene (adeveloper for the first luminous layer) in an ultrasonic bath. Asubstrate in which the first luminous part was protected with thephotoresist was obtained.

The spin coating of the substrate was carried out as the second luminouslayer by dropping 2 ml of a 1 wt % xylene solution of luminescentpolymer MEH-PPV, which is a polyparaphenylene vinylene derivative (shownin the above chemical formula (2)), in the center part of the substrate.A layer was formed by holding the spin coated substrate at 2000 rpm for10 seconds. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous parts of the first and second luminous layers was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part. After being post baked at 120° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with xylene (a developer for the second luminous layer) in anultrasonic bath. A substrate in which the first and second luminousparts were protected with the photoresist was obtained.

After that, all of the photoresist were removed with acetone to make thepatterned luminous layer expose.

On the substrate obtained after drying at 100° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

Here, the solubility of the first luminous layer in xylene, which is asolvent for forming a luminous layer and a developer for a luminouslayer in the second luminous layer, was 0.01 g/g solvent at 25° C. under1 atmospheric pressure and the solubility of the second luminous layerwas 0.1 g/g solvent.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode side and Ag electrode side were connected to a positiveelectrode and a negative electrode, respectively, and were applied withdirect current from a source meter. When 10 V was applied, luminescencewas observed from the second luminous layer, and when 20 V was applied,luminescence was observed from the first luminous layer. And no colormixture was caused.

Comparative Example 1

An element was manufactured similarly to examples except that the firstluminous layer was formed with the use of MEH-PPV and the secondluminous layer was formed with the use of polyvinylcarbazole. As aresult, the first luminous layer flowed out to cause color mixture whenthe second layer was applied and when the second layer was developed,and no good pattern was obtained.

At this time, the solubility of the first luminous layer in toluene,which is a solvent for forming a luminous layer and a developer for aluminous layer in the first luminous layer, was 0.1 g/g solvent at 25°C. under 1 atmospheric pressure and the solubility of the secondluminous layer was 0.1 g/g solvent at 25° C. under 1 atmosphericpressure.

Example 9 The Wavelength of Luminescence in a Luminous Layer

(The Film Formation of a Buffer Layer.)

A patterned ITO substrate of 6 inches square and 1.1 mm in thickness waswashed and used as a substrate and the first electrode layer. The spincoating of the substrate was carried out by dropping 0.5 ml of a coatingliquid for a buffer layer (Baytron P made by Bayer AG, and shown in theabove chemical formula (1)) in the center part of the substrate. A layerwas formed by holding the spin coated substrate at 2500 rpm for 20seconds. As a result, the film thickness became 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the buffer layer should be removed was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist and bufferlayers of the exposed part. After being post baked at 120° C. for 30minutes, all of the photoresist were removed with acetone and the bufferlayer that is insoluble in acetone was formed in an optional pattern.

(The Film Formation of a Luminous Layer)

The spin coating of the substrate where the buffer layer had beenpatterned was carried out as the first luminous layer by dropping 2 mlof a 2 wt % toluene solution of polyvinylcarbazole (shown in the abovechemical formula (3)), a blue color luminescent material, in the centerpart of the substrate. A layer was formed by holding the spin coatedsubstrate at 2000 rpm for 10 seconds. As a result, the film thicknessbecame 800 Å.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous part of the first luminous layer was exposed to ultravioletlight. The exposed layer was developed with a resist developing solution(NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, and thenwashed with water to remove the photoresist of the exposed part. Afterbeing post baked at 120° C. for 30 minutes, the luminous layer on thepart where the photoresist had been removed was removed with toluene inan ultrasonic bath. A substrate in which the first luminous layer wasprotected with the photoresist was obtained.

The spin coating of the substrate was carried out as the second luminouslayer by dropping 2 ml of a 1 wt % toluene solution of luminescentpolymer MEH-PPV, which is an orange color luminescent material and apolyparaphenylene vinylene derivative (shown in the above chemicalformula (2)), in the center part of the substrate. A layer was formed byholding the spin coated substrate at 2000 rpm for 10 seconds. As aresult, the film thickness became 800 Å. The second luminous layer waspeeled off together with the photoresist formed on the upper parts ofthe patterned first luminous layer by peeling off the photoresist withacetone to make the patterned first luminous layer expose.

The spin coating of the substrate was carried out by dropping 2 ml ofpositive photoresist liquid (OFPR-800 made by Tokyo Ohka Kogyo Co.,Ltd.) in the center part of the substrate. A layer was formed by holdingthe spin coated substrate at 500 rpm for 10 seconds and then holding at2000 rpm for 20 seconds. As a result, the film thickness became about 1μm. The layer was prebaked at 80° C. for 30 minutes. After that, thelayer was set together with an exposure mask in an alignment exposuredevice and the part where the luminous layer should be removed exceptthe luminous parts of the first and second luminous layers was exposedto ultraviolet light. The exposed layer was developed with a resistdeveloping solution (NMD-3 made by Tokyo Ohka Kogyo Co., Ltd.) for 20seconds, and then washed with water to remove the photoresist of theexposed part. After being postbaked at 120° C. for 30 minutes, theluminous layer on the part where the photoresist had been removed wasremoved with toluene in an ultrasonic bath. A substrate in which thefirst and second luminous parts were protected with the photoresist wasobtained.

After that, all of the photoresist were removed with acetone to make thepatterned luminous layer expose.

On the substrate obtained after drying at 100° C. for 1 hour, Ca wasvapor deposited in the thickness of 500 Å as the second electrode layer(an upper electrode), and further Ag was vapor deposited in thethickness of 2500 Å as a protective layer. An EL element was thusmanufactured.

(The Evaluation of the Luminous Properties of the EL Element.)

ITO electrode side and Ag electrode side were connected to a positiveelectrode and a negative electrode, respectively, and were applied withdirect current from a source meter. When 20 V was applied, luminescencewith a peak wavelength around 430 nm resulting from polyvinylcarbazolewas observed from the first luminous layer, and when 10 V was applied,luminescence with a peak wavelength around 590 nm resulting from MEH-PPVwas observed from the second luminous layer.

At this time, it is expected that part of polyvinylcarbazole flows outin the second luminous layer from the edge part of the first luminouslayer and mixes with MEH-PPV at the luminous part of the second luminouslayer, however no luminescence resulting from polyvinylcarbazole wasobserved.

Comparative Example 2

An element was manufactured similarly to examples except that the firstluminous layer was formed with the use of MEH-PPV and the secondluminous layer was formed with the use of polyvinylcarbazole.

ITO electrode side and Ag electrode side were connected to a positiveelectrode and a negative electrode, respectively, and were applied withdirect current from a source meter. When 10 V was applied, luminescencewith a peak wavelength around 590 nm resulting from MEH-PPV was observedfrom the first luminous layer, and when 10 V was applied, luminescencewith two peaks around 430 and 590 nm resulting from polyvinylcarbazoleand MEH-PPV, respectively, was observed from the second luminous layer.

The cause was that when the second luminous layer was applied, MEH-PPVflowed out from the edge part of the already patterned first luminouslayer and mixed with polyvinylcarbazole to cause color mixture at theluminous part in the second luminous layer.

1. A method for producing an electroluminescent element, wherein at least one organic electroluminescent layer constituting the electroluminescent element is patterned by the use of a photolithography method.
 2. The method for producing an electroluminescent element according to claim 1, wherein said organic electroluminescent layer patterned by the use of a photolithography method is a luminous layer.
 3. The method for producing an electroluminescent element according to claim 2, wherein said luminous layer is insoluble in a photoresist solvent, a photoresist developing solution, and a photoresist peeling liquid, and a photoresist is insoluble in a solvent used in forming said luminous layer.
 4. The method for producing an electroluminescent element according to claim 2, wherein said luminous layer is a luminous layer in which different types of luminous layers are formed by the use of the photolithography method in plural times.
 5. The method for producing an electroluminescent element according to claim 4, wherein a solvent used for forming luminous layers, which are formed in 2 times and after in said luminous layer, is a poor solvent to the previously formed luminous layer.
 6. The method for producing an electroluminescent element according to claim 5, wherein the solubility of the previously formed luminous layer to a solvent used for forming luminous layers to be formed in 2 times and after is 0.1 g or less/g solvent at 25° C. under 1 atmospheric pressure.
 7. The method for producing an electroluminescent element according to claim 4, wherein the formation of said luminous layers to be formed in plural times is in the order of the short wavelength of light obtained from said luminous layers.
 8. The method for producing an electroluminescent element according to claim 4, wherein said luminous layers are three types of luminous layer emitting red, green and blue light.
 9. The method for producing an electroluminescent element according to claim 1, wherein said organic electroluminescent layer patterned by the use of a photolithography method is a buffer layer.
 10. The method for producing an electroluminescent element according to claim 9, wherein said buffer layer is insoluble in a photoresist solvent and a photoresist peeling liquid and a photoresist is insoluble in a solvent used for forming said buffer layer.
 11. The method for producing an electroluminescent element according to claim 10, wherein after a buffer layer that is insoluble in a photoresist solvent, a photoresist peeling liquid and a solvent to be used for forming a luminous layer is patterned by the use of a photoresist that is insoluble in a solvent to be used for forming the buffer layer, a luminous layer that is insoluble in the photoresist solvent, the photoresist developing solution and the photoresist peeling liquid is patterned and formed by the use of a photoresist that is insoluble in the solvent to be used for forming the luminous layer.
 12. The method for producing an electroluminescent element according to claim 1, wherein said pattering by the use of a photolithography method is a patterning that after a photoresist is patterned in such a way that the photoresist is applied on an organic electroluminescent layer to be patterned, exposed and developed, the organic electroluminescent layer in the part where the photoresist has been removed is removed with dry etching.
 13. The method for producing an electroluminescent element according to claim 12, wherein said dry etching is reactive ion etching.
 14. The method for producing an electroluminescent element according to claim 12, wherein a simple substance of oxygen or a gas containing oxygen is used in said dry etching.
 15. The method for producing an electroluminescent element according to claim 12, wherein atmospheric-pressure plasma is used in said dry etching.
 16. The method for producing an electroluminescent element according to claim 1, wherein said pattering by the use of a photolithography method is a patterning that after a photoresist is patterned in such a way that the photoresist is applied on an organic electroluminescent layer to be patterned, exposed and developed, the organic electroluminescent layer in the part where the photoresist has been removed is removed in an ultrasonic bath.
 17. An electroluminescent element comprising at least one patterned organic electroluminescent layer, wherein the electroluminescent element does not have any one of a partition, a structure aiding patterning, and surface treatment aiding patterning.
 18. An electroluminescent element comprising at least one organic electroluminescent layer, wherein said electroluminescent element layer is a patterned luminous layer, and the width of an area with uneven film thickness that is formed at the end of said patterned luminous layer is 15 μm or less.
 19. An electroluminescent element comprising at least one organic electroluminescent layer, wherein said organic electroluminescent layer is plural patterned luminous layers that can emit light with plural colors, and the distance between the adjacent luminous layers emitting different colors is 30 μm or less.
 20. An electroluminescent element according to claim 18, wherein the electroluminescent element comprises at least a substrate, an electrode layer formed on said substrate in the form of a pattern, and an insulating layer that is formed so as to cover the edge part of said electrode layer and the non-luminous portion of the element. 